Lawrencium (Lr)
Lawrencium (Lr) is element 103 of the periodic table, an actinide in period 7 and group 3. It has no stable isotope and no standard atomic weight; 262 is the mass number of its longest-lived isotope. At room temperature it is a solid.
| Atomic number | 103 |
|---|---|
| Symbol | Lr |
| Standard atomic weight | [262] (mass number of the longest-lived isotope) |
| Molar mass | [262] g/mol |
| Category | Actinide |
| Group | 3 |
| Period | 7 |
| Block | d-block |
| Electron configuration | [Rn] 7s2 5f14 6d1 |
| Oxidation states | +3 |
| Electronegativity (Pauling) | 1.3 |
| Atomic radius (van der Waals) | — |
| First ionisation energy | — |
| Electron affinity | — |
| State at room temperature | Solid |
| Melting point | 1900 K (1626.85 °C) |
| Boiling point | — |
| Density | — |
| Discovered | 1961 |
Group 3
Calculate with Lawrencium
Atomic weight: IUPAC CIAAW — no standard atomic weight; mass number in brackets. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.